X-ray protective combination lock dial assembly



March 13, 1

6 V H. MILLER 3,024,640

X-RAY PROTECTIVE COMBINATION LOCK DIAL ASSEMBLY Filed May 5, 1959 IN VENTOR 'ATTORNE'YS States The present invention relates in general to theart of combination locks, and more particularly to combination lockshaving a facility associated therewith for resisting compromise ofsecurity by X-ray or other radiation means.

It has been known for some time that the security of conventionalcombination locks in safes or other security closures may be compromisedby radiography techniques as, for example, by making X-ray pictures byphotographing high energy radiation which has passed through the lockmechanism. If the dial is manipulated in a special manner and the dialreadings are recorded at the time the film is exposed to the radiationpassing through the lock mechanism, the combination of the lock may bedetermined by observing the differences of photographic densityresulting from the effects of the high density metallic tumblers and thevoids at the location of the peripheral tumbler gatings.

In order to discourage this form of compromise of security, locks havebeen developed in which low density material, such as nylon, is used forthe tumblers, and scattering material and shielding material is placedin the safe on all sides of the look. A radiograph of this lookconstruction, when all of the lock elements are stationary does notreveal the location of the tumbler notches and hence can not be reliablyused by unauthorized persons to detect the combination of the lock.

It has been discovered, however, that if an X-ray film magazine isplaced in a special holder which may be removably attached to the dialof such a combination lock having low density tumbler material so thatthe X-ray film and dial rotate in unison, and if the dial and filmholder are rotated at a uniform rate while an X-ray source placed at therear of the safe directly behind the dial is emitting radiation, it ispossible to detect the combination of the lock. By such a technique, thestationary parts of the lock including the scattering material tend toproduce a uniform background on the radiograph or X-ray picture sincethey are in motion with respect to the film. However, those parts of thecombination lock, including the three peripheral gatings on the tumblerwheels, which are in synchronous rotary motion with the film are clearlyoutlined and are visible in the radiograph. If suitable markers areprovided on the film or the film mechanism the combination of the lockcan be established as one of six possible sets of numbers. Thus the useof stationary scattering and shielding material and low density tumblermaterial does not, in itself, afford adequate protection againstcompromise of security of the safe by radiography.

It has been heretofore proposed in patent application Serial No. 770,390filed by Oleg C. Enikeieif on October 29, 1958, now Patent No.2,970,217, which patent application has been assigned to Grey B. Millerand me as the sole general partners of Harry C. Miller Company, toprovide combination looks with a disk-like X-ray scattering elementwhich is disposed between the tumbler and driving cam assembly and thefront wall of the lock case, or between the front wall of the lockcasing and the dial, and which is keyed to the dial spindle to rotatesynchronously with the spindle, for the purpose of distorting aphotographic image produced in the manner described in the precedingparagraph. This arrangement, however, contemplates the production ofsuch an X-ray 3,024,640 Patented Mar. 13, 1962 scattering element as aseparate member which must be assembled with the remainder of the lockcomponents, and which either necessitates modification of the design ofthe lock casing and some of the components therein or the production ofa special type of mounting plate for supporting the lock casing from thesafe door or other supporting surface.

An object of the present invention, therefore, is the provision of novelmeans incorporated in the construction of a combination lock forresisting compromise of security of the look by radiation techniques.

Another object of the present invention is the provision of novel X-rayscattering means in the dial and dial ring assembly of a combinationlock for distorting X-ray and like radiation energy patterns when theradiant energy is directed through the lock to prevent the production ofradiographs which would reveal the combination of the lock or facilitatecompromise of its security.

Another object of the present invention is the provision of a novel dialand dial ring assembly for combination locks having scattering materialarranged in a stationary component of the assembly and scatteringmaterial arranged in a rotatable component of the assembly, bothdisposed in protective relation to the lock mechanism whereby thestationary and rotatable scattering material cooperate to prevent theproduction of radiographs of the X-ray energy directed through the lockmechanism which would reveal the locations of the tumbler wheel gatings.

Other objects, advantages and capabilities of the present invention willbecome apparent from the following detail description, taken inconjunction with the accompanying drawing illustrating one preferredembodiment of the invention.

In the drawings:

FIGURE 1 is a vertical section view taken through the medial plane of acombination lock dial and dial ring assembly embodying the presentinvention, the dial and dial ring being shown in exploded relation;

FIGURE 2 is a front elevation of the dial ring viewed from the plane 2-2of FIGURE 1;

FIGURE 3 is a rear elevation of the dial member, taken along the plane33 of FIGURE 1; and

FIGURE 4 is a vertical section view of the dial ring taken along thesection plane spaced laterally from the center of the dial ring andindicated by the line 4-4 of FIGURE 2.

Referring to the drawings wherein like reference characters designatecorresponding parts throughout the sev eral figures, the combinationlock dial and dial ring assembly of the present invention, indicatedgenerally by the reference character 10, comprises a dial 11 and a dialring 12. The dial ring 12 is designed to be secured to the front surfaceof a supporting wall, such as a safe door, a file cabinet drawer frontwall, or the like, to the rear surface of which the combination lockcasing is secured. The dial 11 is provided with the usual spindle 13which projects through the supporting door or wall and into thecombination lock casing, and is designed to have the usual driving camwhich is located within the casing keyed to the inner end of the spindle13 to be driven thereby and effect adjustment of the tumbler wheels andmovement of the bolt.

The dial and dial ring assembly 10 illustrated in the drawing is of thetype designed to shield the dial graduations and indicia fromobservation by anyone other than the operator, and is of the generaltype disclosed in my prior Patent No. 2,836,052 issued May 27, 1958. Tothis end, the dial ring 12 is provided with the usual circular base 14which is centrally apertured as indicated at 15 to permit the spindle 13to pass therethrough, and

is provided with a forwardly projecting, interrupted annular shieldingflange 16 disposed near the periphery of the dial ring. The shieldingflange 16 terminates a selected, uniform distance to either side of themedial vertical plane through the dial ring in the upper portion of thedial ring, as indicated at 17 and 18, to define an upper sight opening19 bounded by the ends 17, 18 of the shielding flange 16 and an arcuatesurface 20 lying in the circular path of the annular flange 16. A fixedindex mark 21 is located at the center of the sight opening 19. The base14 of the dial ring 12 is provided with a plurality of openings 22extending therethrough, which may be located on the vertical axisthrough the center of the dial ring 12 for accommodating the usualmounting bolts. The central region of the base 14 of the dial ring 12 isprovided with a forwardly projecting boss 23 which surrounds the centralspindle aperture and mounting bolt openings 22 and extends to thevertical plane of the arcuate surface of the sight opening 19.

The front surface of the base 14 is recessed between the boss 23 andshielding flange 16 to provide a cavity 24. The cavity 24 is bounded byan outer, cylindrical side wall 25 aligned with the inner surface of theshielding flange 16 and an inner side wall '26 which is also the sidewall of the boss 23. This recessed cavity 24 is filled with a largenumber of X-ray scattering bodies 27, which may be, for example, Xspherical lead balls potted or imbedded in a suitable carrier, indicatedat 28. The carrier may be paraffin or a thermoplastic or thermosettingplastic composition of the type which may be poured into the cavity 24when the X-ray scattering bodies have been placed therein to retain thebodies in position within the cavity. To further complicate the Xrayscattering pattern, a plurality of additional X-ray scattering bodies29, which may be of larger diameter than the bodies 27, may be providedin a circular zone about the center of the base 14 spaced from thecenter about the same distance as the mounting bolt openings 22, and tothis end circular bores extending from the rear wall of the cavity 24through the rear surface of the base 14 are provided into which theselarger scattering bodies 29 project. It will be understood that thecavity 24 and the bores for the scattering bodies 29 are of sufficientdepth and diameter in relation to the size of the scattering bodies 27and 29 so that the outer surface of the mass of scattering bodies liesflush with or slightly behind the plane of the front surface of the boss23.

The dial 11 may be cast from Zamac or other metallic or plastic castingmaterial and is provided with a central boss formation 30, which in thisembodiment is removably secured to the dial casting, having a socket 31into which the front end of the spindle 13 is tightly fitted. The dial11 comprises a circular or disk-like front wall 32 having a forwardlyprojecting knob 33 at the center thereof, the front wall 32 beinginclined slightly forwardly from the edge of the knob 33 to theperiphery of the wall. An annular flange 34 projects rearwardly from theperiphery of the front wall 32 and forms a cylindrical surface 35 whichbears the dial markings and indicia. The size of the flange 34 is suchas to nest within the shielding flange 16 of the dial ring 12 so thatthe indicia bearing surface 35 lies immediately adjacent the innersurface of the shielding flange 16 and the indicia are shielded fromview when out of registry with the sight opening 19.

This dial construction, as illustrated, provides an annular cavity 36between the annular flange 34 and the central boss 30, which forms aconvenient housing for a potted mass 37 of X-ray scattering bodies of aform similar to the mass of bodies 27 previously described. Thus, aplurality of lead balls or similar bodies, indicated at 38, may bedisposed in the desired pattern within the cavity 36 and a suitablecarrier 39 of paraffin or suitable plastic material may be poured overthe mass of 4 lead balls 38 to retain the scattering bodies in positionwhen the carrier composition sets.

It is desirable to protect the dial assembly against compromise ofsecurity by insertion of the X-ray film in and around the dial betweenthe dial 11 and the dial ring 12. As one example of means for providingsuch protection, the annular rear wall 40 of the annular flange 34 ofdial 11 is formed With a rearwardly opening annular groove 41 which isconcentric with the axis of the dial 11 and the annular flange 34, andthe dial ring 12 may be provided with an annular baffle member 42 seatedin the cavity 24 of the dial ring 12. The baffle member 42 may beconveniently made in the form of a metallic ring having a thin, annular,outwardly projecting flange 43 adapted to project into and have asliding fit with the annular groove 41 in the dial flange 34. The flange43 projects from a very narrow base ring 44 which is adapted to buttagainst the rear wall of the cavity 24. The base ring 44 may be providedwith a pair of diametrically positioned, inwardly projecting mountingears 45 which extend into engagement with diametrically opposed portionsof the boss 23 to hold the baffle 42 in position within the cavity 24.The baffle 42 may be retained in position by mere frictional engagementof the mounting cars 45 with the surfaces of the side wall of the boss23, or by providing diametrically opposite the opening notches orgrooves in the side wall of the boss 23 into which the inner edgeportions of the mounting cars 45 are forced, or by other expedientswhich will be well known to persons skilled in the art. By extending theannular flange 43 into the annular groove 41 in the dial flange 34, thebaffle member 42 shields the area between the dial 11 and dial ring 12against the insertion of an X-ray film in the area surrounding thespindle 13 and thereby prevents circumvention of the protection affordedby the potted X-ray scattering bodies 38 carried by the dial 11. It willbe apparent that other arrangements may be provided which willeffectively shield the area between the dial and dial ring againstintroduction of X-ray film therebetween, the baffle member 42 beingdescribed as one example of a structure that would be effective for thispurpose.

This construction provides an extremely convenient means ofincorporating an effective X-ray scattering feature in a combinationlock dial and dial ring assembly of more or less conventional formwithout necessitating any drastic modification of the dial and dial ringassembly construction. This drastically simplifies manufacture and costof manufacture of combination locks hav ing this feature, and alsopermits the ready modification of existing combination lockinstallations to incorporate the X-ray scattering feature by the simpleexpedient of replacing the existing dial and dial ring assembly.

As explained earlier, it would be possible to compromise the security ofconventional combination locks, even if they were provided with tumblerwheels or low density material by providing an X-ray film holder or jigwhich may be removably supported on the knob of the conventional dial,and disposing an X-ray source or other radiation source at the rear ofthe safe or security closure generally in alignment with the axis of thedial spindle so as to direct the radiation energy forwardly through thelock mechanism and on to the photosensitivll emulsion in the filmholder. However, when the combination lock dial ring assemblyhereinabove described is provided for the combination lock, thestationary mass of radiation scattering bodies 27 and 29 and therotatable mass of radiation scattering bodies 38 are interposed in thepath of the radiation energy between the radiation source and the filmholder, and the mass of scattering bodies 38 rotates in synchronousangular relation with the dial 11, the mass of scattering bodies 38remains stationary relative to the film in the film holder and sodistorts the photographic image as to prevent reduction of thescattering pattern to background status and thus prevents recording of avisible outline of the lock parts including the tumbler wheels whichremain stationary relative to the dial and the mass of scattering bodies38 during manipulation of the dial. The scattering pattern is furthercomplicated by the fact that relative movement occurs between the twomasses 27 and 37 of scattering material. These features all cooperate toprevent recording of a visible outline of the lock parts andparticularly the tumbler wheels which remain stationary relative to thedial and photo-sensitive emulsion in the film holder during manipulationof the dial. Actually, the mass of scattering bodies 38 in the dialcavity 36 would suifice, without the presence of the stationary mass ofscattering bodies 27, to prevent recording of a visible outline of thetumbler wheels by which the lock security could be compromised, but thepresence of the stationary mass affords additional protection againstcompromise of the lock combination by other radiation techniques. Thus,an effective counter measure technique is provided to preventcompromising of the lock security by the technique described above.

While but one specific embodiment of the present invention has beenparticularly shown and described, it is apparent that variousmodifications may be made in the invention without departing from thespirit and scope thereof, and it is desired, therefore, that only suchlimitations shall be placed thereon as are imposed by the appendedclaims.

I claim:

1. A dial for combination locks of the type having coaxially supportedtumbler wheels and a rotatable dial spindle in coaxial relation to thetumbler wheels for adjusting the same, the dial comprising a generallycircular body to be aflixed centrally to and rotated about the axis ofthe dial spindle and having a front face and a rearwardly opening cavitybounded by an outer peripheral wall, said cavity being disposed over anarea to intercept radiation energy directed through the tumbler wheelsof the associated lock along radiation axes lying within selected smallangles of inclination relative to the axis of the spindle and dial, alayer of radiation scattering bodies disposed in a selected patternthroughout said cavity substantially filling said cavity over the entirearea thereof forming a shielding radiation scattering mass to scatterthe radiation energy intercepted thereby and distort the exit radiationpattern to prevent recording of a readable image of the tumblers whichwould reveal the angular position of the tumbler gatings, and a plasticretaining medium filling said cavity to at least the depth of saidbodies in which said bodies are imbedded to retain the same in theselected pattern within said cavity and cause the layer of bodies torotate as a unit with said dial.

2. A dial for combination locks of the type having coaxially supportedtumbler wheels and a rotatable dial spindle in coaxial relation to thetumbler wheels for adjusting the same, the dial comprising a generallycylindrical dial body having a front wall including an integral knobprojecting centrally therefrom and a cylindrical peripheral surfacebearing dial markings and indicia, said dial body being adapted to 'beafiixed centrally to and rotated about the axis of the dial spindle andhaving a rearward-1y opening annular cavity in coaxial relation with theaxis of the dial body disposed over an area to intercept radiationenergy directed through the tumbler wheels 'of the associated lock alongradiation axes lying within a range of selected small angles ofinclination relative to the axis of the spindle and dial, a layer ofradiation scattering bodies disposed in a selected pattern throughoutsaid annular cavity to form a shielding radiation scattering mass toscatter the radiation energy intercepted thereby and distort the exitradiation pattern to prevent recording of a readable image of hetumblers which would reveal the angular position of the tumbler gatings,and a plastic retaining medium filling said cavity to at least the depthof said bodies in which said bodies are imbedded to retain the same inthe selected pattern within said cavity and cause the layer of bodies torotate as a unit with said dial.

3. A dial for combination locks of the type having coaxially supported,rotatable, peripherally gated tumbler wheels and a coaxially relatedrotatable dial spindle for adjusting the tumblers, comprising a dialbody including a disk-like wall portion and a peripheral rearwardlyprojecting flange having a cylindrical outer surface carrying dialmarkings and indicia, a central boss projecting rear- Wardly from saiddisk-like wall to be aflixed to and rotated about the axis of thespindle, said boss terminating in a bearing surface adjacent the centerof the disklike wall spaced rearwardly from said disk-like wall, saidcentral boss and said peripheral flange defining a rearwardly openingcavity therebetween extending over an expense radially *of the center ofthe dial to a radius at least as great as the radius of the tumblerwheels to intercept radiation energy directed through the tumbler wheelsof the associated lock along radiation axes lying within selected smallangles of inclination relative to the axis of the spindle and dial, alayer of radiation scattering bodies of generally sphericalconfiguration disposed closely adjacent to each other and extendingthroughout said cavity substantially to the depth of said boss toscatter the radiation energy intercepted thereby and distort the exitradiation pattern to prevent recording of a readable image of thetumblers which would reveal the angular position of the tumbler gatings,and means for retaining said radiation scattering bodies within saidcavity and causing said bodies to rotate as a group with said dial.

4. A dial and dial ring assembly for combination locks of the typehaving coaxially supported tumbler Wheels and a rotatable dial spindlein coaxial relation to the tumbler wheels for adjusting the same, thedial comprising a generally circular body to be affixed centrally to androtated about the axis of the dial spindle and having a front face and arearwardly opening cavity bounded by an outer peripheral wall, saidcavity being disposed over an area to intercept radiation energydirected through the tumbler wheels of the associated lock alongradiation axes lying within selected small angles of inclinationrelative to the axis of the spindle and dial, a plurality of radiationscattering bodies substantially filling said cavity over the entire areathereof forming a shielding radiation scattering mass to scatter theradiation energy intercepted thereby and distort the exit radiationpattern to prevent recording of a readable image of the tumblers whichwould reveal the angular position of the tumbler gatings, means forretaining said radiation scattering bodies within said cavity, and saiddial ring including a circular base to be disposed in coaxial relationwith said dial having a central aperture for passage of the spindletherethrough, said dial ring having a forwardly opening cavity in thebase thereof extending over an area corresponding generally to the areaof said dial cavity, a plurality of radiation scattering bodiessubstantially filling said dial ring cavity, and means for retaining thelastmentioned radiation scattering bodies in said dial ring cavity.

5. A dial and dial ring assembly' for combination locks of the typehaving coaxially supported tumbler wheels and a rotatable dial spindlein coaxial relation to the tumbler wheels for adjusting the same, thedial comprising a generally cylindrical dial body having a front wallincluding an integral knob projecting centrally therefrom and acylindrical peripheral surface bearing dial markings and indicia, saiddial body being adapted to be aflixed centrally to and rotated about theaxis of the dial spindle and having a rearwardly opening annular cavityin coaxial relation with the axis of the dial body disposed over an areato intercept radiation energy directed through the tumbler wheels of theassociated lock along radiation axes lying within a range of selectedsmall angles of inclination relative to the axis of the spindle anddial, a layer of radiation scattering bodies disposed in touchingrelation to each other extending throughout said annular cavity to forma shielding radiation scattering mass to scatter the radiation energyintercepted thereby and distort the exit radiation pattern to preventrecording of a readable image of the tumblers which would reveal theangular position of the tumbler gatings, a plastic retaining mediumfilling said cavity to at least the depth of said bodies in which saidbodies are irnbedded to retain the same in a selected pattern withinsaid cavity and cause the layer of bodies to rotate as a unit with saiddial, said dial ring including a circular base to be fixed to astationary supporting surface in coaxial, underlying relation with saiddial having a central aperture for passage of the spindle therethrough,said dial ring having an interrupted, forwardly projecting flangeadjacent the periphery of said base to surround the cylindricalperiphery of said dial and a forwardly opening cavity disposed inwardlyof said flange and extending over an area corresponding generally to thearea of said dial cavity, a layer of radiation scattering bodiesdisposed in touching relation to each other extending throughout saiddial ring cavity to form a shielding radiation scattering mass, and aplastic retaining medium within said dial ring cavity having saidradation scattering bodies imbedded therein to retain the same in aselected pattern within said dial ring cavity.

6. A dial and dial ring assembly for combination locks of the typehaving coaxially supported, rotatable, peripherally gated tumbler wheelsand a coaxially related rotatable dial spindle for adjusting thetumblers, comprising a dial body including a disk-like wall portion anda peripheral rearwardly projecting flange having a cylindrical outersurface carrying dial markings and indicia, a central boss projectingrearwardly from said disk-like wall to be aflixed to and rotated aboutthe axis of the spindle, said boss terminating in a bearing surfaceadjacent the center of the disk-like wall spaced rearwardly from saiddisk-like wall, said central boss and said peripheral flange defining arearwardly opening cavity therebetween extending over an expanseradially of the center of the dial to a radius at least as great as theradius of the tumbler Wheels to intercept radiation energy directedthrough the tumbler wheels of the associated lock along radiation axeslying within selected small angles of inclination relative to the axisof the spindle and dial, a layer of radiation scattering bodies ofgenerally spherical configuration disposed closely adjacent to eachother and extending throughout said cavity substantially to the depth ofsaid boss to scatter the radiation energy intercepted thereby anddistort the exit radiation pattern to prevent recording of a readableimage of the tumblers which would reveal the angular position of thetumbler gatings, means for retaining said radiation scattering bodiesWithin said cavity and causing said bodies to rotate as a group withsaid dial, said dial ring including a circular base having an aperturefor passage of the spindle therethrough and an interrupted forwardlyprojecting flange adjacent the periphery thereof to surround theperipheral flange of said dial, and a forwardly opening annular cavitysurrounding said aperture, and a layer of radiation scattering spheresfixed in said dial ring cavity.

7. In a dial and dial ring assembly, the combination recited in claim 4including baffle means supported on said dial ring and projectingforwardly thereof within said dial ring cavity into lapping relationwith the rearward portion of the outer peripheral wall of said dial toshield the space between said dial and dial ring against insertion ofradiation sensitive film therebetween.

8. In a dial and dial ring assembly, the combination recited in claim 5including an annular baffle member having a base portion seated in thedial ring cavity and an uninterrupted annular flange projectingforwardly from said dial ring base, and said dial having a rearwardlyopening, uninterrupted annular groove complementing a portion of saidflange of said baflie member to receive the baflle member flangetherein, said baflle member flange being disposed radially outwardly ofthe radiation scattering bodies disposed in said dial ring cavity toshield the space between said dial ring and said dial from insertion ofradiation sensitive film therebetween.

References Cited in the file of this patent UNITED STATES PATENTS1,781,060 Hill et al. Nov. 11, 1930 2,016,487 Doenges Oct. 8, 19352,675,485 Scag Apr. 13, 1954 2,916,906 Miller Dec. I5, 1959 2,938,374Cirscuolo et al May 31, 1960 2,951,358 Miller Sept. 6, 1960

